1. Field of the Invention
The present invention relates to a controlled delivery system that can be incorporated into hair care products such as shampoos, conditioners, hair styling products, and other hair care products and that effectively delivers a broad range of active ingredients and sensory markers onto hair, prolongs their release rate over an extended period of time, or provides heat triggered release and high impact fragrance xe2x80x9cburstxe2x80x9d upon blow drying the hair. The present invention also introduces a novel concept of synchronizing the release of the active ingredients with that of a sensory marker to convey to the consumer the product performance.
2. Description of the Related Art
Consumers are becoming increasingly educated and expect a high level of sophistication and multi functionality in their hair care products. They expect the product not only to clean, but also condition, nourish, and provide a lasting impression of clean hair and freshness. Consumer acceptance of hair care products is determined not only by the performance achieved with these products but the perception and aesthetics associated therewith. There is also a need to convey to the consumer the product performance and effectiveness (i.e., the hair is clean, the hair is being conditioned and nourished, etc.). Fragrance is an important aspect of the successful hair care products and they can also be utilized, in addition to imparting an aesthetically pleasing odor, to convey the consumer the product performance.
Fragrance creation for hair care products is restricted not only by considerations such as availability and cost, but also by compatibility of the fragrance ingredients with other components in the product composition and the ability of the fragrance ingredients to deposit onto the hair and survive the wash and rinse process. Furthermore, a large amount of fragrance is often lost during the rinse and drying processes, even when the hair is air-dried. Practice has shown that when current commercial hair care products are used, very little of the fragrance is actually substantive onto the hair.
Publications in the prior art indicate attempts to fulfill the foregoing needs to increase the deposition of active ingredients and fragrances onto hair and to hinder or delay their release rate so that the hair is healthier and remains aesthetically pleasing for a prolonged length of time.
A conventional approach that has been described employs emulsions, liposomes, and other lipid vesicles to deposit the active ingredients onto the hair. See U.S. Pat. Nos. 4,942,038; 5,124,081; 5,198,470; 5,330,758; 5,510,120; 5,518,736; 5,591,449; 5,658,575; 5,660,853; 5,741,518; 5,753,241; 5,759,526; 5,773,611; 5,814,343; 5,874,105; 5,885,564; 5,925,364; 6,010,707; 6,015,574; 6,039,936; 6,066,328; 6,071,535; and 6,126,948. These types of systems have the limitation of being unstable, and can only be used for encapsulation of certain types of materials. Stability has limited the use of liposomes for controlled delivery, both in terms of shelf life and after administration.
U.S. Pat. No. 5,354,564 discloses personal care products comprising an aqueous dispersion of particles of silicone wherein said particles have a surface modifier adsorbed on the surface thereof in an amount sufficient to achieve a particle size of less than about 400 nanometers (nm). The particles of this invention contain a discrete phase of silicone having a surface modifier adsorbed on the surface thereof. Suitable surface modifiers can preferably be selected from known organic and inorganic excipients. Such excipients include various polymers, low molecular weight oligomers, natural products and surfactants. Preferred surface modifiers include nonionic and anionic surfactants.
U.S. Pat. No. 5,599,531 discloses the uses of inorganic charged colloidal silica as a carrier system for hair care products. The penetration or absorption of water, oils, collagen, and other materials into the hair is greatly increased by adding a small quantity of inorganic charged colloidal silica to provide an aqueous suspension of the charged colloidal silica particles along with the material to be absorbed into the hair. In coloring hair, dye components can be absorbed into the hair without the use of alkaline solutions which damage the hair, and in perming hair, the disulfide bonds in the hair can be broken by tension caused by swelling due to water absorption in the hair, again without the use of damaging alkaline solutions. It is believed that the porosity and stable hydration of the hair can be varied through altering the electrostatic charge on the hair. The aqueous suspension of charged silica particles applied to the hair appears to alter this charge.
U.S. Pat. No. 5,660,839 discloses incorporating deformable hollow particles into cosmetic and/or dermatological compositions containing fatty substances, for markedly reduce or eliminate the sticky and/or greasy feel attributed to these fatty substances. Preferably, the particles are in the form of hollow microspheres or microbeads, having a particle size ranging from 1 micron to 250 microns, and comprising a copolymer of vinylidene chloride, acrylonitrile and a (meth)acrylate co monomer.
U.S. Pat. No. 5,667,800 discloses an aqueous suspension of solid lipoid nanoparticles, comprising at least one lipid and preferably also at least one emulsifier, for topical application to the body. The nano-particles disclosed are preferably non-ionic and the emulsifiers used in the processing of these particles are preferably chosen from the groups of polyoxyethylene alkyl ethers and sorbitan esters. The particles have a mean particle size of between 50-1000 nm and their concentration is between 0.01-60 wt %, by weight of the suspension. A medicament can be incorporated into the continuous phase of the suspension or in a vehicle, which is added to the suspension. The invention further provides manufacturing methods for the aqueous suspension.
U.S. Pat. No. 5,780,060 discloses microcapsules with a wall of crosslinked plant polyphenols and compositions containing them. The microcapsules are obtained by the interfacial crosslinking of plant polyphenols, particularly flavonoids. When incorporated in a composition such as a cosmetic, pharmaceutical, dietetic or food composition, these microcapsules make it possible to prevent any impairment of this composition, in particular any color modification, while at the same time preserving the activity, especially the anti-free radical and/or antioxidizing activity, of the plant polyphenols, particularly the flavonoids.
U.S. Pat. Nos. 5,851,517 and 5,945,095 disclose compositions including a dispersion of polymer particles in a non-aqueous medium. A dispersion of surface-stabilized polymer particles can be used in a non-aqueous medium, in a cosmetic, hygiene or pharmaceutical composition. The dispersions may, in particular, be in the form of nano-particles of polymers in stable dispersion in a non-aqueous medium. The nano-particles are preferably between 5 and 600 nm in size, given that beyond about 600 nm, the particle dispersions become much less stable. The polymers used can be of any nature, such as radical polymers, polycondensates or polymers of natural origin. These polymers may, in particular, be crosslinked. Among the non-film-forming polymers described are vinyl or acrylic radical copolymers or homopolymers, which are optionally crosslinked, preferably having a Tg of greater than or equal to 40 degree C, such as polymethyl methacrylate, polystyrene, or poly-tert-butyl acrylate.
U.S. Pat. Nos. 5,759,526 and 5,919,487 disclose nanoparticles coated with a lamellar phase based on silicone surfactant and compositions containing them. The nanoparticles, and in particular nanocapsules, provided with a lamellar coating obtained from a silicone surfactant, can be used in a composition, in particular a topical composition, for treatment of the skin, mucosae, nails, scalp and/or hair. Nanoparticles ranging in size from 10 to 1000 nm are composed of a polymer encapsulating an oily phase and coated with a lamellar coating, wherein the lamellar coating comprises at least one silicone surfactant containing at least a oxyethylenated and/or oxypropylenated chain. The nanoparticles preferably range in size from 10 to 600 nm. The polymers constituting the nanoparticles can be biodegradable or non-biodegradable polymers. Poly-L- and -DL-lactides and polycaprolactones are especially preferred as biodegradable polymers. Among non-biodegradable polymers, copolymers of vinyl chloride and vinyl acetate and copolymers of methacrylic acid and methacrylic acid methyl ester are especially preferred.
U.S. Pat. Nos. 6,013,618 and 6,087,322 disclose the use of pro-accords as a method to enhance fragrance performance from personal care products. Typically the pro-accords are comprised of orthoesters, ketals, acetals, orthocarbonates which release two or more fragrance raw materials upon hydrolysis.
U.S. Pat. No. 6,042,792 discloses a controlled, time-release microparticulate active and bioactive compositions (including perfuming compositions) for targeted delivery to services such as skin, hair and fabric and the environment proximate thereto, where the active and bioactive materials have a calculated log P values of between 1 and 8 (P being the n-octanol-water partition coefficient). Such compositions include the active or bioactive material in single phase, solid solution in a wax or polymer matrix also having coated thereon and/or containing a compatible surfactant. Also described are processes and apparatus for preparing such compositions. The emphasis of U.S. Pat. No. 6,042,792 is in engineering the fragrance formulation and thus limiting the type of fragrances that can be used with the system.
U.S. Pat. No. 6,048,520 discloses a transparent leave-on hair treatment composition including capsules of a water insoluble hair-treating compound encased in a shell material, such as gelatin or acacia gum. The capsules have a diameter of about 425 to about 2800 microns and are broken during application of the hair treatment composition to hair or by combing the hair after application of the hair treatment composition. The aqueous leave-on composition is applied to the hair and the water insoluble hair-treating compound is released from the capsules to treat the hair. The shell disintegrates into sufficiently small residual particles such that the physical and esthetic properties of the hair, like shine and combability, are retained.
Cationic deposition polymers have been conventionally used to enhance deposition of certain nonvolatile components from shampoos and other personal cleansing compositions. For example, U.S. Pat. Nos. 5,037,818 and 5,085,857 describe the use of cationic guar gum to enhance the deposition of antidandruff particles and insoluble nonvolatile silicone, respectively. Deposition polymers have also been proposed to enhance the deposition of sunscreen materials from a shampoo composition. In EP 386,898 a cationic polygalactomannan gum derivative is used. WO 95/22311 describes the use of certain cationic polymers to increase the deposition of nonvolatile benefit agents which include silicones, fats and oils, waxes, hydrocarbons, fatty acids and fatty alcohols, lipids, vitamins and sunscreens.
U.S. Pat. No. 6,083,899 discloses fabric softener compositions that have enhanced softening benefits. The fabric softeners consist of a fabric softener active in combination with a cationic charge booster. The cationic charge boosters are suitable for use with any fabric softener active, preferably with diester and diamide quaternary ammonium (DEQA) compounds.
Similar phenomena were also observed for hair care products. U.S. Pat. 3,980,091 discloses that the pretreatment of hair on the human head, preceding shampooing the hair with anionic type hair shampoos, and with compositions for effecting such pretreatment, to obtain highly improved manageability of the hair after shampooing and with improved fullness, combability and other desired properties of the hair. The pretreatment compositions utilize readily water-soluble quaternary ammonium compounds, particularly in combination with certain agents, notably polyethylenimines and N-ethanolacetamide, and desirably together with various supplemental ingredients.
The prior art of which applicant is aware does not set forth a controlled delivery system for hair care products that is highly substantive onto hair, sustain the release rate of active ingredients and a sensory marker or provide heat triggered release of the active agents and high impact fragrance xe2x80x9cburstxe2x80x9d upon blow drying the hair.
The present invention relates to an improved controlled delivery system for hair care products, such as, shampoo, conditioner, hair styling products, and other hair care products, comprising nano-particles formed of hydrophobic polymers and copolymers in combination with cationic charge booster and cationic conditioning agents to improve the system deposition onto hair. The nano particles of the present invention can include active ingredients and sensory markers.
The controlled delivery system of the present invention is a nan-particle having a solid inner core with cationic exterior that confers several advantages as compared with conventional microspheres, lipospheres, and vesicles, including high dispersibility in an aqueous medium, and a release rate for the entrapped substance that is controlled by the hydrophobic material barrier properties as well as the barrier properties of the hydrophilic layer of cationic surfactant. There are also many advantages over other suspension-based delivery systems. Nano-particles have increased stability as compared to emulsion-based delivery systems, including vesicles and liposomes, and are more effectively dispersed than most suspension based systems. Further, the substance to be delivered does not have to be soluble in the vehicle since it can be dispersed in the solid matrix. The nano-particles of the present invention also have a lower risk of reaction of substance to be delivered with the vehicle than in emulsion systems because the vehicle is a solid inert material. Moreover, altering either, or both, the inner solid core or the outer surfactant layer can manipulate the release rate of the substance from the nano-particles. Nano-particles are also easier to prepare than structured vehicles such as lipospheres, and are inherently more stable.
The nano-particles of the present invention have an improved mechanism to enhance the deposition of the particles onto hair. The highly cationic charge density characterizing the nano-particles of the present invention, achieved by the use of cationic conditioning agents in conjunction with cationic charge booster improves the deposition of these particles onto the hair and prevents them from being washed off during the rinse process. The nano-particles of the present invention are believed to attach to the hair surfaces via a complexing interaction between the cationic charge group on the particles and the proteinaceous portion of the hair and thus predispose or condition the surface of the hair so that the nano-particles will then adhere to the surface.
In one embodiment, the present invention provides an improved controlled delivery system for hair care products, that improves the substantivity of active ingredients and sensory markers onto hair by means of bringing the particles onto the hair through treating the hair with hair care products comprising the nano-particles of the present invention. In the hair care industry, the term xe2x80x9csubstantivityxe2x80x9d refers to the deposition of the active ingredients or sensory markers (i.e., fragrance) on the hair and the retention and perception of the fragrance on surfaces treated with hair care product. Particles comprising cationic charge boosters and the cationic conditioning agents either in the particle composition, or at the particles outer surface, were observed to be highly substantive on surfaces such as skin, hair, and fabric.
The delivery system of the present invention enhances the deposition of active agents and sensory markers onto hair, prolongs their release rate over an extended period of time, or release them upon heat treatment such as blow drying the hair. In addition, the release rate of the active agents is synchronized with that of a sensory marker (i.e., fragrance) to convey to the consumer the product performance.
It has been found that increasing the cationic charge density of the particles through the use of cationic charge boosters in conjunction with cationic conditioning agents enhances the adhesion of the particles onto hair. In addition, by incorporating cationic surface-active agents into the nano-particles composition, the system provides improved compatibility of a wide range of active agents and sensory markers in the delivery system, and increases the substantivity of actives that are currently not substantive on hair.
The prior art of which applicant is aware does not set forth a controlled release system which synchronizes the release rate of the active ingredients with that of fragrances or sensory markers to convey the consumer the product performance.
The nano-particles of the present invention are characterized by:
(i) protection of the active ingredients and sensory markers during storage, until needed.;
(ii) enhanced deposition of the active ingredients and sensory markers onto hair;
(iii) the release rate of the active ingredients is synchronized with that of a sensory marker;
(iv) prolong release of the active ingredients and sensory markers over an extended period of time; or
(v) heat triggered release of the active ingredients and high impact fragrance xe2x80x9cburstxe2x80x9d upon blow drying the hair.
The invention also provides a process for producing the nano-particles of the present invention that comprises the steps of:
a) heating the hydrophobic polymers and copolymers to a temperature above the material melting point;
b) dissolving or dispersing the active agents and/or the sensory markers into the melt;
c) dissolving or dispersing the cationic conditioning agents and/or cationic charge boosters in the melt;
d) dissolving or dispersing the cationic conditioning agents, cationic charge boosters, and/or a co-surfactant in the aqueous phase and heating it to a temperature above the melting point of the melt;
e) mixing the hot melt with the aqueous solution to form a suspension;
f) high shear homogenization of the suspension at a temperature above the melting temperature until a homogeneous fine suspension is obtained; and
g) cooling the suspension to ambient temperature to form a fine dispersion.
It is believed that the highly substantive cationic charge booster in conjunction with the cationic conditioning agents in the particles surface becomes associated, in use, with the hair and assist in adhering the particles onto hair through both particle entrainment and electrostatic interactions. The highly cationic charge density of the nano-particles, achieved by the use of cationic conditioning agents in conjunction with cationic charge booster, improves the deposition of these particles onto the hair and prevents them from being washed off during the rinse process. The nano-particles are believed to attach to the hair surfaces via a complexing interaction between the cationic charge group on the particles and the proteinaceous portion of the hair and thus predispose or condition the surface of the hair so that the nano-particles will then adhere to the surface. The hydrophobic polymers and copolymers sustain the diffusion rate of the fragrance through the particles and enable the release of the active ingredients and sensory markers over an extended period of time, or during heat treatment such as blow drying the hair.
Hair treated with hair care products, such as shampoo, conditioners, and the like, comprising the nano-particles of the present invention were observed to exhibit high level of fragrance (high odor intensity) in both the wet and the dry state and fragrance perception on the dry hair has been observed over an extended period of time up to about 24 hours.
The present invention also provides a cost effective controlled delivery system that improves fragrance performance from hair care products.
The invention still further provides hair care products such as shampoo, conditioner, hair styling products, and other hair care products, comprising the nano-particles of the present invention.